Cyanobacteriochrome TePixJ of Thermosynechococcus elongatus harbors phycoviolobilin as a chromophore
Cyanobacteriochrome TePixJ of Thermosynechococcus elongatus harbors phycoviolobilin as a chromophore
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DOI：
10.1093/pcp/pcm106
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发表时间：
2007-09-01
影响因子：
4.9
通讯作者：
Ikeuchi, Masahiko
中科院分区：
文献类型：
--
作者：
Ishizuka, Takami;Narikawa, Rei;Ikeuchi, Masahiko
蓝藻有几个假定的光感受器（指定的蓝藻色素），与已建立的光敏色素相关但不同。来自嗜热蓝藻热共生球菌（Thermosynechococcus elongatus BP-1） （TePixJ_GAF）的趋光性调节因子PixJ的GAF结构域是一种蓝藻色素，它在蓝色光吸收形式（max = 433 nm）和绿色光吸收形式（max = 531 nm）之间表现出可逆的光转换。为了研究TePixJ_GAF色团，我们从异源表达的Synechocystis中制备了TePixJ_GAF色蛋白，并将其变性后与以藻蓝胆素（PCB）为色团的蓝藻光敏色素Cph1进行了光谱分析。结果表明，TePixJ的发色团不是PCB，而是其异构体绿胆素（PVB）。提示TePixJ的步态结构域具有自裂解酶和自异构酶活性。
Cyanobacteria have several putative photoreceptors (designated cyanobacteriochromes) that are related to but distinct from the established phytochromes. The GAF domain of the phototaxis regulator, PixJ, from a thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 (TePixJ_GAF) is a cyanobacteriochrome which exhibits reversible photoconversion between a blue light-absorbing form (max = 433 nm) and a green light-absorbing form (max = 531 nm). To study the chromophore, we prepared TePixJ_GAF chromoprotein from heterologously expressed Synechocystis and performed spectral analysis after denaturation by comparing it with the cyanobacterial phytochrome Cph1 which harbors phycocyanobilin (PCB) as a chromophore. The results indicated that the chromophore of TePixJ is not PCB, but its isomer, phycoviolobilin (PVB). It is suggested that the GAIT domain of TePixJ has auto-lyase and auto-isomerase activities.